The present invention relates to a recording/reproducing apparatus and a recording/reproducing method for recording and reproducing data to and from an optical disc in accordance with an error rate being measured.
Today, public terminals are set up in convenience stores, amusement arcades, railway station premises and other public locations in order to provide a variety of services. Each of these public terminals is connected to various servers corresponding to the services being offered, such as distribution of music data, sale of show business tickets and other products, and printing of picture data picked up by users' digital cameras.
Under a typical service scheme, a user (i.e., customer) may wish to purchase music data through the use of a public terminal capable of offering a music distribution service. In such a case, the user may illustratively take to the public terminal a storage medium compatible with the terminal, load the storage medium through a slot into the terminal, select a desired tune to be purchased by making appropriate operations on a screen of the terminal while watching guiding images on display, specify the way the payment is to be made (e.g., cash, credit card, or ATM card), and get the music data recorded to the storage medium brought in for the purpose.
The public terminal includes among others a recording apparatus for recording data to a loaded storage medium, and a hard disc drive or the like that stores music data constituting a plurality of tunes offered to customers within the framework of the service. In operation, the public terminal retrieves the music data selected by the user from the hard disc drive, causes the recording apparatus to write the selected data to the storage medium brought in by the user, and ejects the data-recorded medium out of the terminal through the slot.
Because the public terminals are set up in convenience stores, amusement arcades, railway station premises and other well-trafficked locations as mentioned above, these terminals are liable to develop irregularities due to airborne dust or other ambient contamination. Since it is virtually impossible for administrators to stand by and monitor each terminal, a failed terminal cannot be serviced immediately.
In view of such eventualities, this applicant has submitted a patent application (Japanese Patent Application No. 2000-302861) disclosing a structure for dealing with troubles within a recording apparatus more efficiently in the public terminal.
The above patent application shows illustratively that the recording apparatus is structured to collect various pieces of maintenance information regarding the failed status inside the apparatus. The maintenance information is acquired in a suitably timed manner by the public terminal from the recording apparatus and transmitted to a control center connected through a communication network.
By analyzing the transmitted maintenance information, the control center can readily localize any failure that may occur in the recording apparatus and identify the type of the failure. If the recording apparatus is found free of fault but the trouble persists, the control center is able to localize the failure somewhere other than the recording apparatus inside the terminal. Where the recording apparatus is compatible with optical discs, the maintenance information may include the accumulated use time and the output level of a semiconductor laser used in an optical pickup of the apparatus. The maintenance information may also contain information indicative of a level of deterioration in performance in proportion to the used time of the semiconductor laser. These pieces of information allow the control center to take preventive measures against possible failures of the recording apparatus. Such measures include illustratively a decision on the timing of replacing particular parts in the apparatus.
At present, however, there can still occur write errors during the recording of data to the storage medium loaded in the recording apparatus despite the apparent absence of any failure as determined from the details of such maintenance information. One probable cause of such errors is the presence of dirt, dust or other contamination on the disc surface. More specifically, if the recording apparatus handles optical discs and if an optical disc brought in by a customer (i.e., user) and loaded into the recording apparatus has a higher level of contamination than tolerated on the surface, the recording apparatus with its optical pickup may perform a data write operation normally but the contamination may still trigger a write error resulting in failed data recording. It might also happen that a greater-than-tolerable amount of dust, dirt or other foreign matters somehow infiltrating into the recording apparatus sticks to the objective lens of the optical pickup and distorts the laser beam emitted through the lens to the signal surface of the disc. This is another probable cause of write errors.
The above-mentioned maintenance information contains information about the operations carried out by hardware or by software in the recording apparatus, including a write and/or read retry count regarding each disc handled. Illustratively, referencing the retry count information makes it possible to determine whether an out-of-tolerance level of contamination exists in the recording apparatus.
However, with such remote fault diagnosis performed correctly, write errors on the storage medium may already have occurred with a relatively high frequency while the public terminal has been operating. Analyzing the maintenance information signifies checking the results subsequent to write errors, not before. In other words, it is very difficult directly to predict and prevent write errors attributable to the presence of ambient dirt or other contamination.
A typical storage medium is a disc cartridge containing an erasable magneto-optical disc 90a. The magneto-optical disc 90a held in the disc cartridge is designed to have music data recorded to its program area. Radially inside the program area is a control area in which is recorded control information (known as the Table of Contents or TOC) for controlling the music data written to the program area. The TOC is updated every time the program area is renewed such as when new music data are written thereto. If a write error disrupts a correct update of the TOC, unlinking can occur between the control area and the music data, which makes it impossible to reproduce all music data that have been preserved by the user on the disc cartridge.